The desire for special rights, far-reaching autonomy or even independence is supported
to a relatively large extent by a belief in the economic strength of the given region. The financial implications resulting from de facto independence go beyond the savings achieved by exiting the regional financial equalisation scheme of the respective country. Despite the fact that advocates of independence like to gloss over the potential risks, even in the event of immediate membership of the single European market and the eurozone there would be a number of potential financial disadvantages:
— Higher costs of borrowing:
The disadvantage of small countries may be illustrated by comparing Germany and Austria. Even though Austria has a higher per capita GDP, lower sovereign debt and a nearly identical unemployment rate, the risk premium on Austrian bonds is higher. Due to the much lower issuance volume Austrian bonds are perceived to be less liquid, so investors demand a liquidity premium. If Scotland had attained independence it would also obtain a good rating, but nonetheless it would have to pay a premium on British bonds. 
For Catalonia, which according to the several rating agencies currently does not even rate as “investment grade” it would be a much more expensive undertaking. While the Basque 
Country and also Navarra currently has a better rating than Spain with some 
agencies, in fact, in the event of independence the implicit central 
government guarantee would disappear, possibly also weighing negatively 
on the rating. Conversely, though, a loss of economically strong regions 
would also jeopardise the Spanish rating and entail higher funding costs.
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— Financial burden from assumption/distribution of legacy debt. 
Both Spanish regions would have to assume a considerable share of Spain's sovereign 
debt. Scotland would also have to shoulder a share of national debt. 
Whether this would be calculated on the basis of relative GDP figures, 
population or past financing balances, would ultimately be decided by a 
political negotiation process. Depending on the division, though, this would 
result in substantial fiscal burdens for the then independent regions.
— Disruptive trade effects:
The rest of Spain is by far the largest trading partner for the Basque Country and Catalonia; the same applies to the United Kingdom in the case of Scotland as well as to Italy with Veneto. This shows that despite the single European market national borders often continue to 
play a significant role. Even though trade between Spain and Catalonia 
would of course not stop altogether, it seems exceedingly unlikely that the 
intensive trade relations would survive a (possibly discordant) separation without sustaining any damage whatsoever. The fact that about three times as many Catalonian goods are “exported" to other regions of Spain as to the geographically comparable and much larger France impressively shows that borders (whether political, linguistic, cultural ...) still play an important part in a united Europe.
It has to be affordable!
At this point it is not our objective to do the sums for every region on how much 
it could gain, or perhaps lose, in the event of separation. However, it is important 
to understand that such an emotionally charged issue may occasionally cloud 
the view of the economic realities. Setting up an independent administration, 
international representative offices, a military defence organisation etc. naturally 
comes at a price. Objectively speaking, there are not many channels via which 
independence can actually generate financial advantages. One of the few, and 
perhaps the most obvious, is the disappearance of financial transfers to other 
parts of the country. Thus, only in a prosperous region (relative to the rest of the 
country) is it possible to maintain the fiction that going it alone would be the 
better option. In other words: one has to be able to afford it.
Frank Zipfel 
Stefan Vetter 
Daniel Pietzker